etcd

etcd is a consistent, distributed key-value store that provides a reliable way to store data that needs to be accessed by a distributed system or cluster of machines. It handles leader elections during network partitions and can tolerate machine failure, even in the leader node.

For MKE 4k, etcd serves as the Kubernetes backing store for all cluster data, with an etcd replica deployed on each MKE 4k manager node. This is a primary reason why Mirantis recommends that you deploy an odd number of MKE 4k manager nodes, as etcd uses the Raft consensus algorithm and thus requires that a quorum of nodes agrees on any updates to the cluster state.

You can configure etcd through the etcd section of the mke4.yaml configuration file, an example of which follows:

spec:
  etcd:
    storageQuota: 2GB
    tlsCipherSuites: TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256

For comprehensive information, refer to the official etcd documentation.